Earlier this month, engineers at the French Space Agency (CNES) reported that its Convection, Rotation and Planetary Transits (CoRoT) spacecraft suffered a possibly fatal computer error, resulting in an inability to relay data from the 30-centimetre telescope.

Launched on Dec. 27, 2006, from the Baikonur Cosmodrome in Kazakhstan, CoRoT is the first space mission that was dedicated to exoplanet discovery. CoRoT accomplished this by looking for worlds transiting, meaning passing in front of, their host stars, causing a very small but discernible periodic dip in brightness.

In order for a transiting exoplanet to be seen, the orbit must be in close-to-perfect alignment with our line of sight. Most exoplanets do not transit their stars at an angle we can see, but space telescopes such as CoRoT and its NASA predecessor Kepler get around this by sampling thousands of stars. The CCD detector of CoRoT is 3.5° degrees in diameter, about seven times the apparent size of the Full Moon.

CoRoT aims in a direction perpendicular to its 827-km polar orbit, offering it a continuous view unobstructed by the Earth. Unlike Kepler, which aims continuously at a patch of sky across the constellations of Hercules, Lyra and Cygnus, CoRoT looks at Serpens Cauda during the northern hemisphere summer season and aims toward the constellation Monoceros in the winter. This is in order to avoid the blinding Sun; plus, scanning the star rich galactic plane gives it the best chance of success.

– CoRoT-4b, a planet which is orbiting a star which maintains a synchronous rotation with the world’s orbital period

– And an array of “Hot Jupiter”-like worlds with orbital periods less than 4 days

CoRoT just celebrated its fifth anniversary of operations earlier this year. The transit method of hunting for exoplanets does have a bias in favor of “Hot-Jupiters” in extremely tight orbits because. Planets extremely close to their host stars are statistically much more likely to transit our line of sight and planets with large radii will produce a more pronounced and discernible “dip” in brightness.

CoRoT is thus far the only orbiting mission that conducts studies in astroseismology, as well. Astroseismology is the study of seismic activity within stars, literally the analysis of “star quakes.” CoRoT has an observing channel sensitive enough to do this, and has begun to open up the field of study of internal activity in nearby stars.

In 2009, a team at the University of Hamburg announced it had teased out evidence for ‘starspots’ (analogous to sunspots) from the data for exoplanet CoRoT-2b.

But CNES engineers haven’t written off CoRoT just yet. CoRoT has already lasted more than double its original 2.5 year lifespan, and plans include operations until 2015 if recovery operations currently underway are successful. Even if CoRoT is permanently silent, it has paved the way for future missions such as NASA’s Transiting Exoplanet Survey Satellite (TESS) and PLAnetary Transits & Oscillations of stars spacecraft (PLATO).

Soon, we may just have knowledge of the “Holy Grail” of exoplanet science; an Earth-like world orbiting within the habitable zone of a nearby star. And CNES’s CoRoT will have paved the way for that legacy, giving SETI scientists a shortlist of candidates to examine for possible life.

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